Neanderthals May Not Have Coexisted with Humans

By Stephen Luntz

The belief that Neanderthals survived in southern Spain for thousands of years after the species had been wiped out elsewhere has been questioned following new dating of what were thought to be some of the last Neanderthal remains.

Modern humans are thought to have reached Spain around 37,000 years ago. In other parts of Europe the arrival of our ancestors coincides, to within 1000 years or so, with the disappearance of Neanderthals. However, in southern parts of the Iberian Peninsula Neanderthal remains have been dated as recently as 35,000 years ago, making them possibly the youngest known Neanderthal remnants.

However, Dr Rachel Wood of the Australian National University’s Research School of Earth Sciences has challenged this dating, noting it is possible for modern carbon in the soil to contaminate older remains.

Wood used a technique called ultrafiltration, which removes the smaller, more mobile organic material and leaves the large amino acids present in collagen behind. While she could find no Neanderthal collagen she was able to get material from ibex bones mixed with those of their hunters. She found that these bones were at least 45,000 years old.

Having published her work in the Proceedings of the National Academy of Sciences Wood says: “Our results cast doubt on a hypothesis that has been broadly accepted since the early 1990s that the last place for surviving Neanderthals was in the southern Iberian Peninsula. Much of the evidence that has supported this idea is based on a series of radiocarbon dates which cluster at around 35,000 years ago. Our results call all of these results into question and suggest that Neanderthals may not have survived any later in this area than they did elsewhere in mainland Europe.”

Genetic evidence, while disputed, appears to suggest that non-African humans have 1–4% Neanderthal DNA. However, the interbreeding this suggests would have happened when our primary ancestors first left Africa, probably in the Middle East. Evidence from much later periods of co-existence is likely to have been wiped out by successive waves of immigration into Europe.

Late Neanderthal tools from Spain do not show evidence that they learned from the new arrivals. This has been used to question claims of cultural imitation from other regions. Wood’s research could reshape this debate, suggesting that co­existence may not have lasted long enough in Spain for the opportunity to arise.